Simulated influences of Lake Agassiz on the climate of central North America 11,000 years ago

摘要: Eleven thousand years ago, large lakes existed in central and eastern North America along the margin of Laurentide Ice Sheet. The large-scale American climate at this time has been simulated with atmospheric general circulation models1,2, but these relatively coarse global models do not resolve potentially important features mesoscale that arise from interactions among atmosphere, ice sheet, proglacial lakes. Here we present simulations 11,000 ago a high-resolution, regional model nested within model. is agreement inferred palaeoecological evidence. Our experiments indicate through feedbacks, annual delivery moisture to Sheet was diminished times large, cold Lake Agassiz relative periods lower lake stands. resulting changes mass balance sheet may have contributed fluctuations margin, thus affecting routing fresh water Atlantic Ocean. A retreating during high level opened an outlet for discharge into Atlantic. subsequent advance due greater associated low could dammed outlet, thereby reducing These variations decisive causing Younger Dryas event3,4.